In vivo delivery vectors are useful for delivering agents to tissues, cells and subcellular locations. The vectors are typically a solid platform upon which a number of substances, such as agents or targeting moieties, may be attached. A number of vectors have been described as suitable for delivering agents as treatments and/or labels to specific tissue, cell or subcellular locations within a body. Such vectors include viruses and the non-viral vectors such as nanoparticles.
Combining non-viral vectors with cell targeting moieties allows non-viral vectors to deliver agents to specific targets. In addition, combining the non-viral vector with a cell penetrating biologic helps ensure that once the vector reaches the target, the agent can be delivered to the inside of, for example, a cell.
The amount of agent that can be delivered per vector depends on several factors including size of the vector to the extent that size increases the amount of surface area available for binding the agent. There is, however, a trade-off between size and ability of the vector and therefore the agent, to be delivered to the target. Through the use of avidin/biotin technology, the amount of agent delivered per vector can be amplified.
A number of substances, such as drugs, peptides, proteins, nucleic acids and carbohydrates can be conjugated with biotin. An avidin molecule binds up to four biotin molecules and thus binds up to four biotinylated agents. Conjugating an avidin molecule to the vector increases the effective surface binding area four-fold.
The ability to deliver the greatest amount of agent with the least amount of carrier is advantageous. For example, some agents, such as ribonucleic acid (RNA) will suffer degradation en route to the target. Thus, in order to help ensure delivery of sufficient amounts of agent to a target site, an increased load to counteract the degradation is advisable. In another example, the targeted area might be small. Increasing the amount of label to the target area increases the ability to visualize the site. Delivering the greatest amount of agent per vector allows for delivery of the greatest amount of the agent.
While the prior art discloses methods for delivering agents to tissues, cells, and/or subcellular locations, it would be beneficial to have a delivery system that would provide high loading capacity of beneficial agents.